Abstract: [Objective] The aim was to establish an HPLC method for assay detection of compound amoxicillin ＆ sulbactam sodium nanoemulsion. [Method] An HPLC system was equipped with a Diamond C18 （250 mmx4.6 mm,5 μm）,using acetonitrile - water -phosphate buffer as mobile phase, and the detective wavelength was 220 nm. [Result ] The amoxicillin within 40-400 μg/mL had good linear relation （r=0.999 0）; the average recovery was 99.9%; the RSD was 0.52%. The sulbactam sodium within 20-200 μg/mL had good linear relation （r=0.999 8）; the average recovery was 99.9%; the RSD was 0.66%. [Conclusion] This method provides reliable quantitative analysis method for controlling quality of compound amoxicillin ＆ sulbactam sodium nanoemulsion.